1. If you're scoring under a 500 its most likely a content gap. You should download Anki and learn how to use it. Anki will make sure that every detail you enter into it will be committed to memory, so its a strong tool to increase your score a solid chunk. Will help you memorize everything from mitosis, to physics formulas to psychological theories.
2. Do UWORLD if you havent yet and have time, its a Great investment. the passages are great and will help you understand AAMC a lot better.
3. If reading is an issue, pick up a book and start reading it. Reading at a fluent pace will help you with your timing. It will also help you with visualizing what you read, which is helpful on every section of the mcat. Read a 300+ page book in 3 days and you'll work much smoother through all the passages.